Integrated Assessment Research

You are here

Integrated Assessment Research

The goal of the Integrated Assessment Research (IAR) program is to advance scientific understanding of the complex interactions, interdependencies, and co-evolutionary pathways of human and natural systems, including interdependencies among sectors and infrastructures. There is a particular emphasis on understanding the energy-water-land nexus under both realistic and idealized forcing scenarios, including the evaluation of scale-aware processes and probabilistic uncertainties that can lead to instability through thresholds and tipping points. The program additionally considers the role of socio-economics, risk analysis, and complex decision theory, as they pertain to describing the evolution and feedbacks within earth system science.

The human-Earth system, including settlements, infrastructure, natural resources, socio-economics, and importantly, interdependent sectors and natural systems, is highly complex and continuously changing. Both strong and weak linkages define the oftentimes non-linear behaviors among components. Stressors, constraints, and other factors affecting change can take many forms and influence the system at varying spatial and temporal scales, oftentimes in unanticipated ways when viewed within the larger system. Consider, for example, the individual and combined effects of changing patterns of weather and its extremes, demographic distributions, economic growth and changes in industrial structure, improvements in technologies (e.g., for producing electricity), depletion of natural resources such as groundwater, or the discovery of new resources or means for resource extraction such as unconventional natural gas, and the evolution of regulatory and other institutional structures. All of these factors influence infrastructures and sectors that in turn can exhibit nonlinear regional responses as part of the earth system.

One major focus of the IAR program is in understanding the growing interdependencies and risks at the intersection of the energy, water and land sectors. The recent disruptive effects and economic losses associated with the growing intensity, frequency, and persistence of droughts, floods, heat waves, and tropical storms in the United States have highlighted the importance of this research and integrated modeling capability. For example, energy is required for water and wastewater treatment, groundwater pumping, and large-scale inter-basin transfers. Needs, risks, and vulnerabilities of the coupled system are large and growing in the face of shifting weather and precipitation patterns, water supplies that depend on increasingly limited groundwater, transitions in regional economic development (including land use), as well as U.S. population shifts. In contrast, approximately 45% of water withdrawals in America’s rivers and streams are for energy applications, ranging from thermo-electric cooling (e.g., fossil and nuclear power plants) to domestic oil and gas recovery. Hydropower is similarly challenged to respond to increasing competition for limited water supply.

Besides the program focus to understand the system dynamics governing interdependencies within the natural-human system, the program seeks to advance our understanding of system nonlinearity and instability associated with multiple stressors that can lead to cascading failures in connected sectors and systems. An important characteristic of nonlinearity and system failure is the probabilistic interdependence near thresholds associated with extreme weather, severe drought, and infrastructure vulnerability. Consequently, the program supports the development of interoperable tools and methods for integration with agile, flexible earth system modeling frameworks, revealing a basic understanding of different levels of complexity required to analyze interdependency.

The most recently closed Announcement (DE-FOA-0000219) requested applications for a single, coordinated research effort that would: 1) advance progress on a select set of major scientific challenges in the field of Integrated Assessment that are widely recognized and confronting the major Integrated Assessment modeling teams, 2) advance methods and capabilities for inter-model testing and diagnostics, and 3) enhance capabilities for multi-model, "ensemble-like" analyses for improved insights in science studies and science-based analyses.

Why the Program's Research is Important

IAR is necessary to understand the nonlinear science involving natural-human interdependency and feedbacks on the earth system. The program helps shape our fundamental understanding of complex stressors on human systems and infrastructure, vulnerabilities and risks at the energy-water-land nexus, multi-sector dynamics, and more generally, implications for regional and global economic development in the face of changing weather patterns and extremes, advances in technology, availability of natural resources, and feedbacks to natural systems, including regional and global climates.

Recent Content

Recent Highlights

While mean annual snowfall is projected to decrease over the northeastern United States by the end of the century, the vast majority of this is associated with a greatly reduced frequency of weak and moderate snowfall events. Large, crippling, nor'easters are forecast to occur with roughly the same...

Historical records show the U.S. West Coast exhibits a wide range of extreme precipitation during the winter (December-February). Understanding the large-scale environmental influences—or forcing—that contribute to this variability is important for improving predictions of regional climate....

The historical role of California’s Sierra Nevada mountain snowpack as a steady source of fresh water will fade due to climate change. In this paper we aim to answer four major questions surrounding the regional spatiotemporal change in Sierra Nevada mountain snowpack such as how it may change in...

This study provides improved quantification of interannual variability (IAV) of power production (AEP) from wind farms over eastern N. America using purpose-performed long-term numerical simulations with WRF. Our analyses indicate it may be appropriate to reduce the IAV applied to preconstruction...

Publications

The northeastern United States is vulnerable to many impacts from snowfall‐producing winter cyclones that are amplified by the proximity of population centers to storm tracks. Historically, climatic snowfall assessments have centered around seasonal means even though local impacts typically occur...

The U.S. West Coast exhibits large variability of extreme precipitation during the boreal winter season (December–February). Understanding the large-scale forcing of such variability is important for improving prediction. This motivates analyses of the roles of sea surface temperature (SST) forcing...

The mountains of the Western United States provide a vital natural service through the storage and release of mountain snowpack, lessening impacts of seasonal aridity and satiating summer water demand. However, climate change continues to undermine these important processes. To understand how...

Humidity is a key determinant of heat wave impacts, but studies investigating changes in extreme heat events have not differentiated between events characterized by high temperatures and those characterized by simultaneously elevated temperature and humidity. The authors present a framework, using...

The interannual variability (IAV) of expected annual energy production (AEP) from proposed wind farms plays a key role in dictating project financing. IAV in preconstruction projected AEP and the difference in 50th and 90th percentile (P50 and P90) AEP derive in part from variability in wind...